Historically, urine has been utilized as the primary specimen for the detection of drug use in standard toxicology protocols and drug monitoring programs. The monitoring ensures compliance with treatment regimens and assess potential drug abuse. In both scenarios, the analysis of urine samples primarily targets the metabolite(s) of drugs in the body. Detection of these compounds is facilitated by the relatively high concentration of analyte present in the urine specimen in addition to a reasonably long detection window. However, urine drug testing is limited by the fact that results solely indicate past exposure to the detected compounds. Urine is not an acceptable matrix for determining impairment or pharmacological effects, or to estimate dose compliance based on drug concentrations. Currently, blood is the preferred specimen for assessing impairment based on biologically active drug levels in an individual or determinations as to the minimum dose consumed to produce the corresponding concentrations in the body.
As explained, urine cannot provide a satisfactory sample for analysis to determine impairment, pharmacological effects, or dose compliance. Thus, against this background, improved systems and methods to determine body drug concentration from an oral fluid are desirable.